Control of semiconducting oxide gas-sensor microstructure by application of an electric field during aerosol-assisted chemical vapour deposition

Tungsten oxide thin films were deposited on gas sensor substrates from the aerosol assisted chemical vapour deposition of [W(OPh)(6)] in toluene at 600degreesC. It was found that application of an electric field during deposition encouraged thicker film growth. The morphology of the tungsten oxide film could be altered by using stronger electric fields and by use of both direct and alternating currents. In particular the use of alternating currents produced aligned fibrous growth between the electrode gaps of the sensor substrate. This morphology produced a tungsten oxide gas sensor that was particularly sensitive to low concentrations of nitrogen dioxide.